256677731 has 2 divisors, whose sum is σ = 256677732. Its totient is φ = 256677730.

The previous prime is 256677719. The next prime is 256677739. The reversal of 256677731 is 137776652.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256677731 is a prime.

It is a super-2 number, since 2×256677731² = 131766915182616722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256677739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128338865 + 128338866.

It is an arithmetic number, because the mean of its divisors is an integer number (128338866).

Almost surely, 2^256677731 is an apocalyptic number.

256677731 is a deficient number, since it is larger than the sum of its proper divisors (1).

256677731 is an equidigital number, since it uses as much as digits as its factorization.

256677731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 370440, while the sum is 44.

The square root of 256677731 is about 16021.1650949611. The cubic root of 256677731 is about 635.5202556394.

The spelling of 256677731 in words is "two hundred fifty-six million, six hundred seventy-seven thousand, seven hundred thirty-one".